WASHINGTON (AP) — President Barack Obama says he'll work with Congress to help the public understand the circumstances under which the government will target an American citizen with ties to al-Qaida using an unmanned aerial drone.

Obama says he doesn't believe a president can do whatever he wants, whenever, under the guise of counterterrorism.

And, he says it's not enough for U.S. citizens to take his word that, quote, "we're doing the right thing."

An internal Justice Department memo surfaced earlier this month outlining a legal rationale for the government to target U.S. citizens abroad it believes are leaders of al-Qaida and continually engaged in operations against Americans.

Obama commented Thursday during an online chat sponsored by Google. He says a drone has never been used against an American citizen on U.S. soil.